Summary
SiYuan: Missing publish-access check on getBlockBreadcrumb, getRefText, and getBlockTreeInfos discloses content and metadata of protected/forbidden documents
CVE: This vulnerability corresponds to CVE-2026-72805.
Three block endpoints return document content snippets and metadata without any publish-access check, while their sibling getBlockInfo which returns comparable data does enforce one. All three are CheckAuth-only, so they are reachable by the publish RoleReader token and by the anonymous account when Publish.Auth.Enable is false. An anonymous reader supplying a block ID receives content and metadata belonging to publish-forbidden and password-protected documents.
Details
getBlockInfo (kernel/api/block.go) gates on the publish boundary:
if !checkBlockPublishAccess(c, id, ret) {
return
}
The following siblings in the same file perform no equivalent check:
| Endpoint | Returns | Publish check |
|---|---|---|
getBlockInfo |
root/title/path metadata | checkBlockPublishAccess: present |
getBlockBreadcrumb |
BlockPath.Name : root document title plus every ancestor block's content snippet |
none |
getRefText |
the block's reference/anchor text (document content) | none |
getBlockTreeInfos |
root/title/path metadata for arbitrary block IDs | none |
getBlockBreadcrumb returns the full ancestor chain including each ancestor block's content snippet, and getRefText returns block anchor text both are document content, not just metadata. getBlockTreeInfos returns root/title/path for any caller-supplied ID set via model.GetBlockTreeInfosInBox(...) with no gate.
getBlockBreadcrumb and getRefText additionally accept a client-supplied notebook argument that routes to the *InBox variants, so the same unguarded path applies to encrypted-notebook reads while the notebook is unlocked.
The correct primitive already exists in the codebase and is used by getBlockInfo; these three handlers simply do not call it.
Proof of Concept
Precondition: publish mode enabled (default port 6808); anonymous when Publish.Auth.Enable is false, otherwise any publish reader account. A document D is marked publish-forbidden (or password-protected) and contains a block BLOCK_ID under a heading with distinctive content.
Control: the gated sibling correctly refuses:
POST http://127.0.0.1:6808/api/block/getBlockInfo
{"id":"BLOCK_ID"}
Blocked by checkBlockPublishAccess.
Disclosure: the ungated siblings return the data anyway:
POST http://127.0.0.1:6808/api/block/getBlockBreadcrumb
{"id":"BLOCK_ID"}
→ ancestor chain including the forbidden document's title and ancestor block content snippets
POST http://127.0.0.1:6808/api/block/getRefText
{"id":"BLOCK_ID"}
→ the block's reference/anchor text (content of the forbidden document)
POST http://127.0.0.1:6808/api/block/getBlockTreeInfos
{"ids":["BLOCK_ID"]}
→ root ID, title, and path for the forbidden document
Verified by code inspection at origin/master (eef10568): getBlockInfo contains the checkBlockPublishAccess call; getBlockBreadcrumb, getRefText, and getBlockTreeInfos contain no publish-access, publish-ignore, or readonly-role check in their bodies.
Impact
An anonymous reader (publish mode with auth disabled) or any publish RoleReader can read, for documents explicitly excluded from publishing or protected by a publish password:
- the document title and full ancestor chain, including ancestor block content snippets (
getBlockBreadcrumb); - block reference/anchor text, i.e. document content (
getRefText); - root ID, title, and path metadata for arbitrary block IDs (
getBlockTreeInfos).
Because getBlockBreadcrumb and getRefText accept a notebook argument routing to the *InBox variants, the same disclosure applies to encrypted notebooks while unlocked. Confidentiality-only; the precondition is a block ID, obtainable from other reader-reachable endpoints.
The application does not perform an authorization check before performing a sensitive operation. Typical impact: unauthorized access to restricted functionality or data.
CVE-2026-72805 has a CVSS score of 5.8 (Medium). The vector is network-reachable, no privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (0.0.0-20260723163028-931ba693375e); upgrading removes the vulnerable code path.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
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See it in your environmentNew to Kodem? Get a demo →Remediation advice
Call checkBlockPublishAccess (as getBlockInfo does) in getBlockBreadcrumb, getRefText, and getBlockTreeInfos before returning data for getBlockTreeInfos, apply it per ID and drop unauthorized entries. Confirm the *InBox variants (GetBlockRefTextInBox, BuildBlockBreadcrumbInBox) enforce the same boundary so the notebook-argument path is covered.
Frequently Asked Questions
- What is CVE-2026-72805? CVE-2026-72805 is a medium-severity missing authorization vulnerability in github.com/siyuan-note/siyuan/kernel (go), affecting versions < 0.0.0-20260723163028-931ba693375e. It is fixed in 0.0.0-20260723163028-931ba693375e. The application does not perform an authorization check before performing a sensitive operation.
- How severe is CVE-2026-72805? CVE-2026-72805 has a CVSS score of 5.8 (Medium). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
- Which versions of github.com/siyuan-note/siyuan/kernel are affected by CVE-2026-72805? github.com/siyuan-note/siyuan/kernel (go) versions < 0.0.0-20260723163028-931ba693375e is affected.
- Is there a fix for CVE-2026-72805? Yes. CVE-2026-72805 is fixed in 0.0.0-20260723163028-931ba693375e. Upgrade to this version or later.
- Is CVE-2026-72805 exploitable, and should I be worried? Whether CVE-2026-72805 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2026-72805 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix CVE-2026-72805? Upgrade
github.com/siyuan-note/siyuan/kernelto 0.0.0-20260723163028-931ba693375e or later.